Bulldozer blade mounting

ABSTRACT

A bulldozer blade mounting for minimizing mechanical stresses during tilting of the blade and for maintaining generally constant blade pitch during raising and lowering of the blade, comprising three generally parallel members pivotally mounted between the blade and its supporting vehicle. Two of the members are parallel push arms arranged in a generally horizontal plane relatively adjacent the base of the blade. The third member is an extendible link arranged in a generally central location between the vehicle and an upper portion of the blade to provide triangular support for the blade and to permit pitching of the blade.

United States Patent Inventor Leon A. Wirt Joliet, lll. Appl. No. 752,873 Filed Aug. 15, 1968 Patented July 6, 1971 Assignee Caterpillar Tractor Co. Peoria, 111.

BULLDOZER BLADE MOUNTING Sword Primary Examiner-Robert E. Pulfrey Assistant Examiner-Stephen C. Pellegrino Attorney-Fryer, Tjensvold, Feix, Phillips and Lempio ABSTRACT: A bulldozer blade mounting for minimizing mechanical stresses during tilting of the blade and for maintaining generally constant blade pitch during raising and lowering of the blade, comprising three generally parallel members pivotally mounted between the blade and its supporting vehicle. Two of the members are parallel push arms arranged in a generally horizontal plane relatively adjacent the base of the blade. The third member is an extendible link arranged in a generally central location between the vehicle and an upper portion of the blade to provide triangular support for the blade and to permit pitching of the blade.

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PATENTEU JUL 6191! SHEET 5 OF 5 INVENTOR LEON A. WIRT 5M 7% ATTORNEYS Bl LLDOZER BI. \DE 01 \TINU In addition to firmly supporting the blade upon a suitable vehicle. a mounting for a bulldozer blade must commonly permit varied motion ofthe blade. for example, raising and lower' ing, pitching, tilting, and angling. Providing for tilting of the blade has been a particular problem. Most prior art designs, for example, permit tilting of the blade about a longitudinal axis through the vehicle only with accompanying bending or torsional stresses which may be particularly severe within portions of the mounting or within the blade itself. For reliable operation and reduced breakage of the blade and mounting components, it is desirable to minimize these stresses during tilting of the blade. It is also desirable to construct the blade mounting so that blade pitch remains substantially constant while the blade is being raised and lowered.

The present invention overcomes these problems through the use of a mounting assembly comprising three generally parallel members forming substantially a triangular support for the blade. According, it is an object of the present invention to provide a bulldozer blade mounting which permits the blade to be tilted with substantially reduced stresses in the blade and mounting.

It is a further object to employ one of the parallel members of regulating blade pitch.

It is also an object to provide a bulldozer blade mounting which maintains generally constant blade pitch while the blade is being raised and lowered. Preferably the mounting causes the blade to be pitched slightly forwardly as the blade is being lowered to facilitate blade penetration.

It is a further object to provide additional means for angling the blade.

It is a still further object to maintain minimum outside dimensions for a vehicle supporting a bulldozing blade by means of the present mounting.

Additional objects and advantages of the invention are made apparent in the following description having reference to the accompanying drawings:

In the drawings:

FIG. 1 is a side view in elevation of a vehicle with a bulldozer blade attachment;

FIG. ,2 is an enlarged side elevation view of the forward end of the vehicle with one wheel removed to more clearly illustrate the mounting assembly;

FIG. 3 is a plan view of the forward end of the vehicle and the mounting assembly for the blade;

FIG. 4 is a view similar to FIG. 2 illustrating an alternate embodiment of the invention; and

FIG. 5 is a plan view of the forward end of the vehicle and the alternate mounting embodiment of FIG. 4.

Referring to FIG. 1, the mounting assembly of the present invention is indicated at 11 for supporting a blade 12 upon a vehicle 13 which is preferably of an articulated, wheel type. The blade 12 is of a generally conventional type having a cutting edge 14 mounted along its lower extremity with a skid plate 16 secured to the blade behind the cutting edge. The vehicle has a pair of forward wheels, one of which is indicated at 17, and a pair of rearward wheels, one of which is indicated at 18.

The blade mounting assembly 11 is illustrated in greater detail in FIGS. 2 and 3. A pair of push arms 19 and 21 are secured by ball and socket joints 22 and 23 to mountings 24 and 26 which extend forwardly from the vehicle 13. The ball and socketjoints 22 and 23 for the push arms are adjacent the axle 27 for the forward wheel and are further arranged inside of the wheel 17 to provide minimum overall dimensions for the vehicle with the bulldozer blade attached. The forward ends of the push arms 19 and 21 are secured generally to the base of the bulldozer blade 12 by means of respective ball and socket joints 28 and 29.

An upper link 31 is mounted between the vehicle and a generally central portion of the blade by means of respective ball and socket oints 32 and 33 so that the upper link 31 is generally parallel with the lower push arms 19 and 21. The ball and socket oint 33 is supported by a bracket 34 mounted at the rear of the blade 12. Accordingly. the upper link 31 and the two push arms 19 and 21 provide triangular support for the bulldozer blade 12. As best seen in FIG. 2, the pair of lower push arms 19, 21, the upper link 31 form two sides of a quadrilateral or more specifically, a trapezium. One other side of the quadrilateral is formed by the vertical distance between the ball and socket joint'32 for the upper link and the ball and socket joints 22, 23 for the lower push arms. The fourth side of the quadrilateral is formed by the rear of the bulldozer blade or more particularly the vertical distance between the ball and socket joint 33 of the upper link and the ball and socket joints 28, 29 of the lower push arms.

The lengths of the members 31 and 19, 21 together with the generally vertical spacings between the ball and socket joints may be selected so that the blade experiences no forward or rearward pitching during raising and lowering of the blade. However, the lengths and spacings referred to above are preferably selected to form the trapezium indicated in FIG. 2 so that the top of the blade pitches slightly forward as its cutting edge is lowered toward the ground. In this manner, the cutting edge 14 is automatically placed below the skid plate 16 as the blade is lowered to facilitate its penetration into the ground.

To raise and lower the blade, a pair of links 36 and 37 are respectively secured to the push arms 19 and 21 adjacent the blade 12 by means of ball and socket joints 38 and 39. The links 36 and 37 extend generally upward toward pivotal connections 41 and 42 with levers 43 and 44, respectively. The levers 43 and 44 are stabilized by means of a spreader beam 46 secured thereacross and are pivoted to the vehicle 13 at 47 and 48, respectively. The lever 43 is a bellcrank having an arm 49. A hydraulic jack 51 is pivoted to the vehicle 13 at 52 while its rod 53 is pivoted at 54 to the arm 49. Extension and retracting of the jack 51 rotates the levers 43 and 44 to raise and lower the blade 12 by means of the links 36 and 37.

To tilt the blade about a generally longitudinal axis of the vehicle, the vertical link 36 includes a hydraulic jack 56 having a rod 57 which is extended or retracted to tilt the blade 12. Because of the triangular support for the blade 12 and the ball and socket or biaxial connection for the mounting members 19, 21 and 31, the blade may be tilted from from substantially increased stresses in either the blade or the mounting members.

To further stabilize the mounting assembly for the blade, diagonal bracing members 58 and 59 are formed integrally with the push arms 19 and 21, respectively, and extend inwardly to terminate generally adjacent the center of the blade 12. The diagonal bracing members 58 and 59 are secured to each other in articulated fashion by means of a ball and socket 61. The diagonal bracing member 58 is pivotally secured to a bracket 62 mounted on the rear of the blade by means of a short link 63 which is also pivoted to a bracket 64 secured to the bracing member 58. A pin 66 which forms the pivotal connection for the bracket 64 and link 63 also extends toward the center of the blade to form the ball and socketjoint 61. By this arrangement, as the blade is tilted, the diagonal bracing members 58 and 59 move in articulated relation to each other while the short link 63 permits limited motion of the blade relative to both of the diagonal bracing members 58 and 59. Accordingly, undesirable bending or torsional stresses which would develop in the push arms or in the blade during tilting motion is eliminated. The manner in which the diagonal bracing members 58 and 59 are secured to each other and to the blade is set forth in greater detail in US. Pat. No. 3,490,821, issued Aug. 21, 1962 to R. W. Lichti and assigned to the assignee of the present invention.

An alternate embodiment of the blade-mounting assembly is illustrated in FIGS. 4 and 5 and has the additional function of providing for angling of the blade generally about a vertical axis through the center of the blade. Components which are similar to those described with reference to H05. 2 and 3 indicated by primed numerals similar to those used above. Unlike the embodiment in FIGS. 2 and 3, the ball and socket joints 33', 28 and 29' join the mounting members 31, 19 and 21' to a reinforced support member 71 instead of the blade 12' directly. The blade is pivotally secured to the support member 71 by a pair of vertical pivots 72 and 73.

The blade, in combination with the support member 71, is raised and lowered, pitched and tilted in a similar manner as for the embodiment described in FIGS. 2 and 3. However, the blade 12' is additionally free for angling about the axis of the vertical pivot 72 as is illustrated by the broken line representation of the blade in an angled position in FIG. 5. To control angling of the blade, hydraulic jacks 74 and 76 are pivoted to the support member 71 at 77 and 78, respectively, on opposite sides of the pivot 72, 73 for the blade. The jacks 74 and 76 have rods 79 and 81 which are secured to the blade by respective pivots 82 and 83. The jacks 74 and 76 are reciprocably extended and retracted for angling of the blade in either direction. For example, retracting of the jack 74 and extension of the jack 76 angles the blade 12' into the position illustrated in broken lines in FIG. 5.

What I claim is:

l. A mounting arrangement for supporting a bulldozer blade assembly upon a vehicle, comprising a push arm pivotally interconnected between each side of the vehicle and a respective side of the blade assembly generally at its base,

an elongated member pivotally interconnected between the vehicle and a central portion of the blade assembly above the pivotal connections between the blade assembly and push arms,

lift means for raising and lowering the blade relative to the vehicle, the means comprising a generally vertical link pivotally connected with each respective push arm and lift motor means interconnected between the vehicle and both of the links, and

tilt means for tilting the blade about a longitudinal axis of the vehicle, the tilt means comprising a hydraulic cylinder forming at least a portion of one of the vertical links, said lift motor means and said vertical link being interconnected by lever means pivoted upon the vehicle, and connected to each link, and a spreader beam rigidly interconnected between the levers, and so that the tilt cylinder is operable independently of the lift motor means with minimum stress being developed in the mounting arrangement and blade assembly.

2. The invention of claim 1 where one of the levers is a bellcrank with a side arm, the lift motor means being a hydraulic cylinder interconnected between the vehicle and the side arm.

3. The invention of claim 1 wherein the elongated member, the push arms and the generally vertical spacing of the respective pivots for the member and push arms form a quadrilateral, the lengths of the member and push arms and the vertical spacing being selected to pitch the blade slightly forwardly as it is lowered to improve blade penetration.

4. The invention of claim 1 wherein the elongated member is biaxially pivoted to the vehicle and blade assembly and includes motor means for varying blade pitch.

5. The invention of claim 4' wherein the pivotal connections on the push arms and elongated member are ball-and-socket joints.

6. The invention of claim 1 further comprising diagonal bracing members extending inwardly from the push arms and an articulated joint between the inwardly extending ends of the members, one of the bracing members being connected with the blade assembly for stability of the blade and mountmg.

7. The invention of claim 6 wherein the one bracing member is connected with the blade assembly by means of a linkage permitting limited motion of the blade assembly toward and away from the diagonal bracing members. 

1. A mounting arrangement for supporting a bulldozer blade assembly upon a vehicle, comprising a push arm pivotally interconnected between each side of the vehicle and a respective side of the blade assembly generally at its base, an elongated member pivotally interconnected between the vehicle and a central portion of the blade assembly above the pivotal connections between the blade assembly and push arms, lift means for raising and lowering the blade relative to the vehicle, the means comprising a generally vertical link pivotally connected with each respective push arm and lift motor means interconnected between the vehicle and both of the links, and tilt means for tilting the blade about a longitudinal axis of the vehicle, the tilt means comprising a hydraulic cylinder forming at least a portion of one of the vertical links, said lift motor means and said vertical link being interconnected by lever means pivoted upon the vehicle, and connected to each link, and a spreader beam rigidly interconnected between the levers, and so that the tilt cylinder is operable independently of the lift motor means with minimum stress being developed in the mounting arRangement and blade assembly.
 2. The invention of claim 1 where one of the levers is a bellcrank with a side arm, the lift motor means being a hydraulic cylinder interconnected between the vehicle and the side arm.
 3. The invention of claim 1 wherein the elongated member, the push arms and the generally vertical spacing of the respective pivots for the member and push arms form a quadrilateral, the lengths of the member and push arms and the vertical spacing being selected to pitch the blade slightly forwardly as it is lowered to improve blade penetration.
 4. The invention of claim 1 wherein the elongated member is biaxially pivoted to the vehicle and blade assembly and includes motor means for varying blade pitch.
 5. The invention of claim 4 wherein the pivotal connections on the push arms and elongated member are ball-and-socket joints.
 6. The invention of claim 1 further comprising diagonal bracing members extending inwardly from the push arms and an articulated joint between the inwardly extending ends of the members, one of the bracing members being connected with the blade assembly for stability of the blade and mounting.
 7. The invention of claim 6 wherein the one bracing member is connected with the blade assembly by means of a linkage permitting limited motion of the blade assembly toward and away from the diagonal bracing members. 